Add memif - packet memory interface for intra-host communication

Change-Id: I94c06b07a39f07ceba87bf3e7fcfc70e43231e8a
Signed-off-by: Damjan Marion <damarion@cisco.com>
Co-Authored-By: Milan Lenco <Milan.Lenco@pantheon.tech>
diff --git a/src/vppinfra/clib.h b/src/vppinfra/clib.h
index 0386c75..fbb2a21 100644
--- a/src/vppinfra/clib.h
+++ b/src/vppinfra/clib.h
@@ -100,6 +100,12 @@
 /* Full memory barrier (read and write). */
 #define CLIB_MEMORY_BARRIER() __sync_synchronize ()
 
+#if __x86_64__
+#define CLIB_MEMORY_STORE_BARRIER() __builtin_ia32_sfence ()
+#else
+#define CLIB_MEMORY_STORE_BARRIER() __sync_synchronize ()
+#endif
+
 /* Arranges for function to be called before main. */
 #define INIT_FUNCTION(decl)			\
   decl __attribute ((constructor));		\